Field of the Invention
The present invention relates to a light emitting diode (LED) package and a method of fabricating the same, and more particularly, to an improvement of an LED package, which includes a light-transmittable encapsulation member for encapsulating an LED chip and a housing configured to surround the encapsulation member.
Discussion of the Background
An LED is a semiconductor light emitting device in which a current is supplied thereto and electrons and holes may be recombined in p-n semiconductor junctions to emit light. Conventionally, the LED is fabricated as a package structure including an LED chip, and the light emitting device configured as described above may be generally referred to as an “LED package.”
Generally, the LED package includes a base which is mounted with the LED chip and is provided with electric terminals, and a light-transmittable encapsulation member which is configured to protect the LED chip. A lead frame or a printed circuit board (PCB) has been prevailingly used as the base which is mounted with the LED chip. Depending on what is used as the base, the LED package may also be classified into a lead frame type LED package and a PCB type LED package. Further, an additional component such as a heat sink may also be used as the base which is mounted with the LED chip.
The lead frame type LED package includes a housing for defining a cavity in which the encapsulation member is formed. Such a housing generally serves to reflect light in order to narrow a viewing angle, i.e., in order to collect light, so that the housing has been referred to as a reflector. In the LED package as described above, the housing is formed of an opaque resin material by an ejection molding process and then a liquefied light-transmittable resin is injected into the cavity of the housing in a dotting manner to thereby form the encapsulation member.
It is conventionally difficult to design and fabricate the LED package with a viewing angle of light variably changed. This is because the design for the light viewing angle of the housing primarily depends on the shape for the reflection surface of the housing (in particular, the angle for the reflection surface). Further, since there is a large difference between the molding method of the housing and the molding method of the encapsulation member, it is difficult to consecutively fabricate the LED package and the fabrication process for the LED package is cumbersome and complicated.
According to the technique in which a liquefied resin is injected into the cavity of the ejection-molded housing in a dotting manner to form the encapsulation member, the encapsulation member is configured to have an undesired, upwardly convex shape due to the surface tension exerted on the liquefied resin. The shape of the encapsulation member deteriorates various performances of the LED package in the optical aspect. For example, if the LED package fabricated as described above is employed in a back light, the convex portion of the encapsulation member faces a light guide plate, thereby generating a hot spot phenomenon, i.e., a phenomenon in which there exists a point-shaped region excessively brighter than other regions. At this time, it is noted that such a convex shape of the encapsulation member as described above is different from that of the convex lens that is designed as required to control the viewing angle of light. On the other hand, if the amount of the liquefied resin injected into the cavity is reduced, there is generated an undesired, concave shape to thereby decrease the light emitting efficiency of the LED package.